QUESTION 1. [26 Marks] In Fig. 1, shaft I, made from alloy steel (hot-rolled) with tensile strength Su-320 MPa and yield strength S-180 MPa, is welded to a fixed support and is subjected to loading by equal and opposite forces F via shaft II. The length of the shaft | from the fixed support to the connection at shaft II is 1 meter. The force F oscillates between 0.5 and 2 kN. The theoretical stress concentration factor K, introduced by the 3 mm fillet is 1.6. Assume that the notch sensitivity is 1. Find the safety factor for the infinite life for shaft 1. Use the modified Goodman fatigue failure criterion. Hint: Use the Distortion Energy (von Mises) theory to estimate the relationship between the tensile and torsional strength.